Summary

We've covered a lot of stuff in this chapter! We introduced three new language features: class methods, which are methods that are handled by the class itself instead of a particular instance; the @encode() directive used for methods that need a description of a C type to do their work; and fast enumeration.

We looked at a number of useful Cocoa classes, including NSString, NSArray, and NSDictionary. NSString holds human-readable text, while NSArray and NSDictionary hold collections of objects. These objects are immutable: they can't change after you create them. Cocoa provides mutable versions of these classes, which let you change their contents at will.

Despite all our efforts (and despite the length of this chapter), we've just barely scratched the surface of the hundreds of different classes in Cocoa. You can have fun and get smarter by digging around and learning about more of these classes.